Analyzing the Maryland Case on a Statewide Basis

The Supreme Court’s new partisan gerrymandering case features a district-specific (rather than a statewide) claim, as the plaintiffs challenge only Maryland’s Sixth Congressional District. It’s worth noting, though, that had the plaintiffs attacked Maryland’s entire congressional map, they (likely) would have been entitled to prevail under the test adopted by the Whitford trial court:

Discriminatory intent: Democrats had unified control of the Maryland state government in 2011, and it’s evident from the Benisek record that they sought to benefit themselves, and disadvantage Republican candidates and voters, when they redrew Maryland’s congressional districts.

Discriminatory effect: Maryland’s congressional plan had an average pro-Democratic efficiency gap of about 13% in the 2012, 2014, and 2016 elections. Only eight plans over the last half-century have been more skewed, on net, and five of those are currently in effect. It would also take a nine-point pro-Republican swing for Republicans to capture even a single additional seat. The Maryland map’s tilt is thus impervious to most electoral shifts.

Justification: Compared to hundreds of maps simulated by Jowei Chen and David Cottrell, Maryland’s congressional plan is much more skewed in a Democratic direction. It’s therefore improbable that Maryland’s political geography or legitimate redistricting objectives can explain the plan’s tilt. (To prove this point, however, more detailed simulations incorporating Maryland’s specific line-drawing goals would be necessary.)

To be clear, district-specific and statewide theories of partisan gerrymandering don’t always point in the same direction. In a subsequent post, I’ll explore where the theories converge and where they diverge. At least in Benisek, though, both types of claims support the invalidation of Maryland’s congressional plan.